New record of larval-pupal endoparasitoid Exorista deligata parasitising Indian Tea looper Hyposidra talaca from India

Abstract

For the first time, we report the occurrence of Exorista deligata (Pandellé, 1896) (Diptera: Tachinidae) parasitising Hyposidra talaca (Walker) (Lepidoptera: Geometridae), a major invasive pest of Indian Tea, Camellia sinensis (L) Kuntze (Theaceae). The looper pest, H. talaca, completes about 6 to 8 generations per year without diapause on C. sinensis, resulting in heavy crop loss. The field-collected larvae and pupa of H. talaca were reared until the emergence of either adult Hyposidra or parasitoid (Exorista) and subsequently investigated for parasitoid infestations. We observed the immature stages of the parasitoid (larva, pre-pupa, and matured pupa) inside the developing pupa of H. talaca, with complete devouring of the host. The adult parasitoid was identified as E. deligata with the help of morphological characteristics and confirmed by molecular technique, i.e., mitochondrial cytochrome c oxidase subunit I (COX-CO1-700bp) gene sequencing, BLAST and phylogeny matching analysis. The species is infrequent, and its parasitoid nature is still unexplored, except for its occurrence on certain hosts. The percent pupal mortality of H. talaca caused by E. deligata was calculated (mean 25.4%, range 5.88%-57.69%) as proof of the findings in light of its possible role as a biological control agent to address the damage mitigation against the tea looper pest, H. talaca in future.